Indiana Department of Natural Resources

Originally found in Arizona, TCD affects many types of walnut trees to varying degrees but is lethal to black walnuts, which often are grown in plantations in Indiana but also are common in the state's urban and rural forests.

TCD is spread by walnut twig beetles carrying a newly identified fungus (Geosmithia morbida). Smaller than a pinhead, the beetles bore into walnut branches, feeding on the tree's bark tissues and depositing the fungus that creates a canker, or dead area, under the bark. Multiple feedings cause the formation of thousands of cankers under the bark and destroys the tree's ability to transport water and nutrients. Gradually, branches die, and then the entire tree.

Walnut trees affected by the disease typically die within two to three years after symptoms are noticed. However, one study monitoring walnut trees with TCD in Virginia and Tennessee reported recovery of the dieback symptoms which may be associated with drought recovery.

Geosmithia morbida was isolated from a native weevil, Stenomimus pallidus in a black walnut plantation in Yellowwood State Forest in Brown County in December 2013. This was the first time the fungus was detected on an insect other than the walnut twig beetle. Geosmithia morbida has not been detected in any other location in Indiana.

The walnut twig beetle was detected in Franklin County in samples collected during the 2014 trapping season. This is the first detection of walnut twig beetle in Indiana. The detection was from a trap and also from logs at a sawmill. The sawmill is the only quarantined location, and movement of walnut into and out of Franklin county is not regulated.

Surveys are in place at both locations to monitor and evaluate the detections. Visual surveys for the disease symptoms and trapping surveys for the walnut twig beetle are ongoing throughout Indiana with a focus on areas anticipated to be likely introduction points, such as sawmills, concentration yards for log buyers, solid waste sites and other woodworking sites.

Indiana Quarantine Information

Moving walnut material inside IndianaDue to the TCD find in Yellowwood State Forest, Brown County, the plantation has been quarantined. This restricts the movement of black walnut out of the plantation. Movement of black walnut within Indiana from other areas of Brown County and the rest the state is not restricted.

Transporting walnut material OUT of IndianaDue to the TCD find in Indiana, other states have restricted the movement of Indiana walnut material into or through their states. These restrictions vary from state to state. Please contact an Indiana Compliance Officer for the most recent restrictions and to obtain a compliance agreement or state phytosanitary certificate to facilitate the movement of this material.